The present invention relates to drive mechanisms for cylinders of a rotary printing press.
Cylinders of a rotary printing press with bearing rings are generally known from DE 195 01 243 A1. Additional lubricant is applied to these bearing rings as a function of a torque taken up by a drive motor of the cylinder.
DE 37 07 996 C2 discloses a device for affecting the bearing ring pressure in order to compensate for the effects of temperature changes.
DD 207 359 C describes cylinders of a web-fed rotary printing press with bearing rings of different sizes.
U.S. Pat. No. 3,196,788 discloses transfer cylinders of a printing press with two bearing rings of different size, wherein one bearing ring is assigned to the associated form cylinder, and the second bearing ring is assigned to the associated plate cylinder. In this case, bearing rings of equal size roll off on each other.
The object of the present invention is directed to providing drive mechanisms for cylinders of a rotary printing press.
The object is attained in accordance with the present invention by providing bearing rings for two cooperating cylinders of a rotary printing press. The ratio of the radiuses of the bearing rings lies within defined limits. A normal force between the two bearing rings can be changed in response to a torque sensed as acting on one of the cylinders.
The advantages which can be obtained by the present invention reside, in particular, in that, in connection with cooperating cylinders or cylinder groups, a power flow which occurs because of unwinding differences is suitably compensated directly between these cylinders. In connection with driving cylinders or cylinder groups, it is possible for unwinding differences to exist between the cylinders, so that a friction torque is created. These differences in the power consumption possibly can require considerable differences in the layout of the drive motors of the cooperating cylinders. For example, by the present invention, it is possible to employ identical drive motors with a reduced total output within a print unit.
With this arrangement, it is also possible to compensate for effects based on temperature differences and to prevent, in this way, an impermissible wear of bearing rings.
The fixed layout of diameters of different sizes of the bearing cylinders of cooperating cylinders is also advantageous in order to achieve power consumptions of approximately the same magnitude of the associated drive motors.